Albion went 1-0 up in the first half thanks to Neal Maupay's 10th goal of the season but the Saints improved in the second period and drew level through lethal striker Danny Ings.
Brighton were then under severe pressure and were grateful to Ryan's sensational save when he turned Jannik Vestergaard's 25-yard strike against the crossbar.
Head coach Potter said: “Maty had a difficult evening against Manchester City and was disappointed.
“But I think he showed the quality of person he is in terms of how he responded and how he helped the team.
“He’s a top professional because he gets on with it and gives his best. Sometimes you’re the hero and sometimes you’re the villain. You have to try and be as consistent as possible, and he’s pretty good at that.”
“Defensively we put our bodies on the line, great blocks, because we needed to.
“Southampton were really good in the second half.
“In the end it is a really good point for us.”
The point at St Mary's places Brighton six points clear of the drop zone with six available. Albion also have a better goal difference and point against Newcastle next Monday would cement their place in the top flight.
"Every point is hard-earned in the Premier League and we have certainly had to work hard for this point,” Potter added.
“It’s another important point to add to the total. We had to survive in the second half because they were clearly better than us.
“In the first half I thought we were okay and had some chances. Then they pushed us back so credit to them, but credit to us too because we blocked shots and put our bodies on the line.
“Before the lockdown we drew at Wolves which isn’t easy and at Sheffield United which also isn’t easy. So we’ve managed to find a little bit of resilience away from home. We saw that tonight. We had to ride our luck which you need and I thought the defensive effort was fantastic.
“We are in a good place but we need to carry on, it’s as simple as that. There are two more Premier League games to go, so we want to get as many points as possible.”
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